// @algorithm @lc id=2107 lang=cpp weekname=weekly-contest-255
// @title find-unique-binary-string


#define print(...)
// @test(["01","10"])="11"
// @test(["00","01"])="11"
// @test(["111","011","001"])="101"
class Solution {
public:
    string findDifferentBinaryString(vector<string>& nums) {
        unordered_set<string> s;
        for(auto &v: nums)
            s.insert(v);
        const int n = nums.size();
        for(int i=0; i<(1<<n); i++){
            string ans;
            for(int k=n-1; k>=0; k--)
                ans.push_back((i&(1<<k)) ? '1' : '0');
            if(!s.count(ans)) return ans;
        }
        return "";
    }
};